What should be your first language?
Well, I would say that it is English or German language. If you search for a job you will find out that almost all companies require knowledge of some foreign language. From my experience it is English and then in many cases German (I live in the Czech Republic). However if you know only German and you do not know English at all it is not very good. In past it was for example Russian. Thus today for sure English is the best choice.
What should be your second language?
In general each additionalmastereda foreignlanguagehelpsto get a job.Especially for companiesfor which isthe foreignlanguagedomestic.From the perspective ofglobalizationisadvisable to choosea languagespoken bymany people.From this perspectiveseems to be veryadvantageousto learnSpanish,Russian, ChineseorArabic.From theEuropeanpoint of viewit is also possibleto considerFrench, GermanorItalian. It is also true that China is getting stronger in our world so if you like Asia you will not regret it.
I would say that every foreign language is useful and important. You only need to manage it at a level of communication.
You do not be translator or interpreter but today you should know very well at least two foreign languages. It will help you find your job for sure.
Good luck 🙂